The present invention relates to a junction circulator for high power, high-frequency use, and more particularly to a junction circulator of the type which includes a cooled ferrite structure disposed in a microwave junction zone where it is exposed to a static magnetic field.
A microwave circulator is a coupling device having a number of ports for connection to microwave transmission lines, such as waveguides or striplines. Microwave energy entering one port of the circulator is transferred to the next adjacent port in a predetermined direction. A threeport microwave circulator, for example, may be used to transfer energy from a klystron connected to the first port to a particle accelerator connected to the second port. Any microwave energy reflected back to the circulator by the particle accelerator then exits via the third port, so that the reflected energy is diverted from the klystron.
High-power circulators, which include cooled ferrite structures exposed to static magnetic fields in microwave junction zones an which were designed specifically for very high power, high-frequency applications, are disclosed by Fumiaki Okada et al in the publications, IEEE Transactions on Microwave Theory and Techniques, Vol. MTT-26, No. 5, May, 1978, pages 364-369, and IEEE Transactions on Magnetics, Vol. MAG-17, No. 6, November, 1981, pages 2957-2960. In the circulators described in these publications, the ferrite structure is composed of a plurality of ferrite discs which are separated from one another by air gaps and which are arranged perpendicularly to the static magnetic field on metal carriers through which a coolant flows.